IRON UPTAKE MECHANISMS OF PATHOGENIC BACTERIA

Most of the iron in a mammalian body is complexed with various protein s. Moreover, in response to infection, iron availability is reduced in both extracellular and intracellular compartments. Bacteria need iron for growth and successful bacterial pathogens have therefore evolved to compete successfully for iron in the highly iron-stressed environme nt of the host's tissues and body fluids. Several strategies have been identified among pathogenic bacteria, including reduction of ferric t o ferrous iron, occupation of intracellular niches, utilisation of hos t iron compounds, and production of siderophores. While direct evidenc e that high affinity mechanisms for iron acquisition function as bacte rial virulence determinants has been provided in only a small number o f cases, it is likely that many if not all such systems play a central role in the pathogenesis of infection.